Hong Kong UNESCO Global Geopark (), formerly Hong Kong National Geopark (香港國家地質公園), was inaugurated on 3 November 2009. It is a single entity of land area over 150 km2 across parts of the eastern and northeastern New Territories. On 18 September 2011, UNESCO listed the geopark as part of its Global Geoparks Network. The Hong Kong UNESCO Global Geopark consists of two geological regions: the Sai Kung Volcanic Rock Region, with its widely distributed tuff volcanic rocks displaying prismatic columnar jointing, which are of international geological significance the Northeast New Territories Sedimentary Rock Region, which comprises sedimentary rocks formed in different geologic periods, showcasing the complete geological history of Hong Kong. History In 2008, the Hong Kong government commissioned a study to investigate the feasibility of establishing a geopark. The study identified two suitable regions, namely the north-eastern New Territories and Sai Kung. The government subsequently set up a geopark to cover both regions. The geopark was formally inaugurated by Chief Executive Donald Tsang on 3 November 2009. Sai Kung Volcanic Rock Region High Island High Island () is the home of the columnar-jointed volcanic tuff. Most of the columns are sub-vertical, straight-sided and parallel. It covers a large area around Sai Kung Peninsula in the eastern part of Hong Kong, including High Island Reservoir and Tai Long Wan. Ung Kong Group Ung Kong Island Group () is located in southeastern Hong Kong, immediately to the south of the High Island peninsula and to the northwest of the Ninepin group of islands. It consists of Wang Chau (), Basalt Island () and Bluff Island (). Columnar-jointed rocks underlie these islands, giving their cliff coastline a distinctive appearance, and leading to the development of many sea caves and sea arches. Ninepin Group Ninepin Group () is located on the eastern side of Hong Kong, forms a series of offshore islands. Numerous inclined columnar jointed volcanic rocks create cliffs and coastal scenery around the Ninepin Group. Columns in the Ninepin Group are as large as 3-meters in diameter. Sharp Island Sharp Island () is located in the Port Shelter, to the southeast of the Sai Kung Town, from where it can easily be reached by small boat. The island is underlain by older volcanic-related sedimentary rocks. There is a tombolo reaching to a small island nearby at low tide. Northeast New Territories Sedimentary Rock Region Double Haven and Port Island Double Haven